We look at how Britain's debt and deficit has changed under Conservative and
Labour governments over the past four decades.

Public sector net debt hit £1 trillion in March 2011, and has continued its steady ascent. The figure has risen from £337bn in 2000, to £1.16 trillion today - and that's excluding bank bail-outs.

As a percentage of national output, net debt fell under Labour when they took power in the mid-1970s, following a double-dip recession caused by an oil crisis.

Britain's debt continued to fall when Margaret Thatcher's Conservative government took power in 1979, dipping to a low of 26pc of GDP in the 1990/91 financial year. It began climbing again on the back of the US savings and loans crisis in the early 90s.

Boom times under Labour also saw the national debt fall to 29.8pc in the 2001/02 financial year, although several bank bail-outs meant net debt soared from 43pc of GDP in the 2007/08 financial year to 150.4pc twelve months later.

Excluding the bail-outs, net debt rose from 36.4pc to 44.5pc.

Under the Coalition Government, net debt excluding bank bail-outs has continued to rise from 57.1pc of GDP when they took power to 71.8pc last year.

When George Osborne became Chancellor, he set himself two targets.

His core “fiscal mandate” was to be on course to balance the books over a rolling five-year period.

His supplementary target was that net public-sector debt would fall as a share of GDP between 2014-15 and 2015-16.

In December, the Office for Budget Responsibility (OBR) said that Mr Osborne was likely to miss this second target

It forecasts that debt to GDP, excluding bail-outs will climb to 74.7pc of GDP in 2012/13, and will not begin to fall until the 2016-17 financial year.

Deficit

The Government deficit is the gap between what it spends and what it gets in income, mainly from taxes.

Since 1974, there have only been eight years when the Treasury has ended the year in the black.

Four of them were under Labour, and four under the Conservatives.

As a proportion of GDP, Britain's deficit ballooned in the wake of the financial crisis, jumping to 109pc in 2009 and 10.1pc a year later, according to OECD figures.

The latter number is bigger than bailed-out Portugal, at 9.8pc and close to Greece's deficit that year of 10.8pc.